The present invention relates broadly to a bed assembly which utilizes an air mattress for at least a portion of the body supportive surface of the bed. More specifically, the present invention relates to a bed assembly wherein the overall firmness of the air mattress can be adjusted.
Mattresses which utilize air-filled bags or cores are known in the prior art. For example, U.S. Pat. Nos. 954,284 to Hecht; 2,000,873 to Arens; and 2,823,394 to Smith each disclose a mattress, a portion of which is filled with air. In the mattresses disclosed in Arens and Smith a central air-filled core is surrounded by padding material.
Bed assemblies which utilize air mattresses and which have some control mechanism to adjust the inflation of the air mattress are also known in the prior art. Examples of such bed assemblies are illustrated in U.S. Pat. Nos. 3,605,138 to Tucker; 3,784,994 to Kery; and 3,822,425 to Scales. Such inflation control mechanisms, however, have generally been complex and utilized valving and/or compressor mechanisms, or individual cell systems. Applicants are unaware of a simple and inexpensive firmness control mechanism for use with an air mattress used in a bed assembly.
U.S. Pat. No. 3,792,501 to Kery, hereinafter Kery '501 patent, discloses several embodiments of air chairs and convertible sofas. The chairs and sofas of the Kery '501 patent utilize air mattress type cushions. Each cushion communicates with an air spring and a specified quantity of air is filled within a respective cushion and air spring. The air springs are spring biased to a collapsed position so that when no pressure is applied to the cushions, the air springs remain completely collapsed. However, when pressure is applied to a cushion, air is forced into and extends the air spring. The firmness of a cushion thus adjusts to the pressure applied. However, a mechanism for adjusting and setting the firmness as disclosed in the present invention is not provided.
Other complex air cushions and air inflation mechanisms for use in automobile seats are disclosed in U.S. Pat. Nos. 2,136,510; 3,326,601; and 3,363,941.